Food irradiation Irradiation is the use of radiation from x-rays or radioactive materials on food. The process sterilizes food and kills bacteria. The benefits of irradiating food include the ability to control insects and bacteria, such as Salmonella . The process can give foods (especially fruits and vegetables) a longer shelf life and cause less food poisoning .

But the topic of irradiation seems to be one surrounded by as much myth as fact. For example, food irradiation does not make the food radioactive, nor will it make you glow in the dark. In fact, it can actually prevent you from taking on the greenish-tinge that comes with food poisoning.

What Is Food Irradiation?

Food irradiation, like pasteurization or canning, is a food safety technology designed to eliminate the germs, bacteria, and parasites that would otherwise cause foodborne diseases from the foods we eat. It is used in more than 60 countries around the world, and endorsed by many health organizations and professional groups, including the World Health Organization, the Food and Agriculture Organization of the United Nations, the US Public Health Service, the American Medical Association, and the American Dietetic Association.

What Is the Purpose of Food Irradiation

According to the US Food and Drug Association Center for Food Safety and Applied Nutrition, there are four main purposes of food irradiation:

  • Preservation—Irradiation extends the shelf life of a food by destroying or inactivating organisms in the food that may cause spoilage and decomposition.
  • Sterilization—Irradiated foods can be stored for years without refrigeration. They are also often used in hospitals for patients with severely-impaired immune systems, such as AIDS patients or people undergoing chemotherapy . Both NASA and the military use irradiated food as a means of preventing foodborne illness.
  • Control sprouting, ripening, and insect damage—Irradiation is sometimes used in place of chemicals to prevent sprouting, ripening, and insect damage. This process is particularly used in products such as potatoes, tropical and citrus fruits, grains, spices, and seasonings. However, because it does not leave a residue on the food, irradiation does not protect against reinfestation as insect sprays and fumigants do.
  • Control foodborne illness—Irradiation effectively destroys organisms such as Salmonella that can cause foodborne illness.

What Does the Process of Irradiation Involve?

The process of food irradiation involves passing a source of ionizing energy through the food to destroy any harmful bacteria and other organisms. Technically, there are three different methods of food irradiation:

  • Gamma rays
  • Electron beams
  • X-ray irradiation

Gamma ray irradiation is the oldest form of irradiation technology. It is used to sterilize medical, dental, and household products. It is also used to treat cancer. This method of irradiation uses a form of one of two radioactive elements: cobalt 60 or cesium 137. The gamma rays given off by these elements are capable of penetrating foods to a depth of as much as several feet.

With electron beam irradiation, a stream of high energy electrons are shot through an electron gun. It is used to treat foods that are one inch or less in thickness. This type of irradiation has been in use for over 15 years.

X-ray irradiation is the newest form of irradiation. It is essentially a more powerful version of the x-rays you would receive in your doctor’s office. It works by directing a beam of electrons at a thin plate of gold or other metal, producing a stream of x-rays on the other side. Like gamma radiation, x-rays can pass through thick foods. No radioactive elements are involved in x-ray irradiation.

How Does Irradiation Affect Foods?

Despite some of the myths you may have heard, food irradiation does not change the nutritional value of the food or make it dangerous to consume. Some foods may be slightly warmed by the process and others may taste somewhat different. (Imagine the difference in taste between pasteurized and unpasteurized milk).

Afterwards, irradiated foods can be stored, handled, and cooked in exactly the same way as unirradiated food.

How Can I Tell If my Food Has Been Irradiated?

In general, the changes to food caused by the irradiation process are so minimal that distinguishing an irradiated food from a nonirradiated food can be quite difficult. In the US, all manufacturers of irradiated foods are required to put an international symbol, called the Radura, on their products and to include a description of the process on their product labels.

A Final Word

It is important to remember, however, that purchasing irradiated food is no guarantee of its safety. Food irradiation does not replace proper food production, processing, handling, or preparation, nor can it enhance the quality of or prevent contact with foodborne bacteria after irradiation. Therefore, the rules of basic food safety must still be followed:

  • Raw meat, fish, poultry, and dairy products should be as fresh as possible at the time of purchase. Buy products with the longest shelf life.
  • Place raw meat, poultry, and fish away from any cooked foods or fresh produce in the grocery cart.
  • Store refrigerated foods below 40°F.
  • Wash hands before, during, and after food preparation.
  • Store all leftovers within one hour by placing them in tightly sealed, shallow containers.
  • Eat leftovers within three to four days for maximum enjoyment and safety.